Currently there are a large number of Bluetooth audio products in the market facilitating audio transmission between paired Bluetooth devices for example, one of a host computing device such as a general purpose computer, tablet, smartphone or smartwatch; and a microphone, headphone or headset. Almost all devices employ one of two profiles: HFP (Hands-Free Profile)/HSP (Headset Profile) for voice communication; and Advanced Audio Distribution Profile (A2DP) for playing music.
HFP describes how a host computing device, e.g. a mobile phone, can be used to place and receive calls for a hands-free device, a headset. HFP supports all the features supported by HSP. The only difference between HFP and HSP is that HFP supports additional features e.g. Call Waiting (CW). A typical configuration for HFP is an automobile using a mobile phone as a Bluetooth host. In the automobile, the vehicle audio system can be used for the phone audio and a microphone is installed in the car for sending outgoing audio. HFP can also be used for a personal computer to act as a speaker phone for a mobile phone in a home or office environment. Both HFP and HSP use Synchronous Connection Oriented (SCO) to carry a low quality mono-audio channel i.e. a mono speaker channel is transmitted to a mono audio receiver and vice versa.
When operating via A2DP, in devices which support both protocols, HFP/HSP are disconnected automatically before A2DP is enabled. Each A2DP service, of possibly many, is designed to uni-directionally transfer an audio stream in up to 2 channel stereo, either to or from the Bluetooth host.
It is desirable however to provide a Bluetooth device which provides high quality bidirectional full duplex audio with a paired device.
U.S. Pat. No. 9,167,086 discloses a wireless headset with audio recording capabilities including a microphone for receiving first audio signals generated by a user, and a BLUETOOTH module for transmitting and receiving wireless radio signals, wherein the wireless radio signals received by the BLUETOOTH module comprise second audio signals. The headset includes an audio encoder/decoder for encoding the first audio signals received by the microphone and the second audio signals received by the BLUETOOTH module to generate data, a loudspeaker, connected to the audio encoder/decoder, for playing the second audio signals to the user, a memory unit for storing the data generated by the audio encoder, and a control unit which is coupled to the audio encoder/decoder for transferring the data to the memory unit.